#!/usr/bin/env python3
#
# Copyright (C) 2019 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#

import sys

from vyos.configtree import ConfigTree


if len(sys.argv) < 2:
    print("Must specify file name!")
    sys.exit(1)

file_name = sys.argv[1]

with open(file_name, 'r') as f:
    config_file = f.read()

config = ConfigTree(config_file)

if not config.exists(['protocols', 'bgp']):
    # Nothing to do
    sys.exit(0)
else:
    # Check if BGP is actually configured and obtain the ASN
    asn_list = config.list_nodes(['protocols', 'bgp'])
    if asn_list:
        # There's always just one BGP node, if any
        asn = asn_list[0]
    else:
        # There's actually no BGP, just its empty shell
        sys.exit(0)

    # Check if BGP scan-time parameter exist
    scan_time_param = ['protocols', 'bgp', asn, 'parameters', 'scan-time']
    if config.exists(scan_time_param):
        # Delete BGP scan-time parameter
        config.delete(scan_time_param)
    else:
        # Do nothing
        sys.exit(0)

    # Save a new configuration file
    try:
        with open(file_name, 'w') as f:
            f.write(config.to_string())
    except OSError as e:
        print("Failed to save the modified config: {}".format(e))
        sys.exit(1)
